Last night, the U.S. Justice Department announced that it would investigate the death of Trayvon Martin, after watching outrage build as Florida authorities appeared to do nothing for 23 days. The 17-year-old Martin was walking through a residential development in Sanford, Fla. and was chased down and shot by a 28-year-old man named George Zimmerman. If this sounds painfully familiar, it should.

Zimmerman had called 911, describing Martin as "a real suspicious guy" who "looks like he's... on drugs or something." Martin was walking home from a 7-11 carrying a bag of Skittles and a can of iced tea. From where he spotted Martin, Zimmerman could determine nothing more than that the teen was guilty of Walking While Black. Zimmerman then said, "These assholes always get away," and chased after Martin, despite the 911 operator's insistence that "we don't need you to do that." On multiple neighbors' calls to 911, Martin can be heard screaming for help. Zimmerman is still not in jail.

Our own Max Read has a good summary of the details of the killing you should read. All of them are disgusting, but what's most depressing is how unsurprising so much of it is.

This could have happened anywhere. Like so many other parts of Florida, Sanford is a little place with a little character ringed with the overwhelmingly white suburban crudscape of gated developments named after the beautiful things that were bulldozed to make them—places where local police and Golf Cops automatically view any black person not behind the wheel of a Honda Odyssey as criminally suspicious. Trayvon could have been shot dead in Hillsborough, Duval, Escambia, or Broward County, too.

Then there's local law enforcement's casual indifference to violence against a black person and even the appearance of aiding to legitimize it. And of course you have state law enforcement murmuring about intervention in a case of violence against a black person only after weeks of building outrage—perhaps because they were too busy fiddling with laws that keep those sorts of folk from votin'.

Then you have Zimmerman's account of self-defense. Florida is a Stand Your Ground state, which—apart from the death penalty and the half dozen massive military installations—is one of the things that makes the state's "CHOOSE LIFE" license plates either hilarious or nauseating, depending on your mood.

(The words "CHOOSE LIFE" are even written in a faux-childish crayon scrawl, making you wonder what the design process was like. "No, make it look shittier!" "It looks pretty childish, already." "No, no, more wobbly! Like she's having trouble writing this through all the tears she's shedding because she's thanking God she wasn't aborted." "I can't believe I owe SCAD $120,000 in loans for this shit.")

Florida's 2005 Stand Your Ground law allows people to use deadly force if they "reasonably believe" that it's "necessary to prevent imminent death or great bodily harm." But unlike Castle Doctrine laws, which amount to "kill the fuck outta anybody who sticks his head in your house," Stand Your Ground doesn't appeal to the primal sense of invasion and self-defense associated with one's own home. Castle Doctrine laws at least rely on the idea that you are confronting someone who has already violated your property or safety, without any input or action from you. Stand Your Ground is a great, legally roving murder bubble.

Here's where Zimmerman's self-defense case should break down. Martin did briefly get in a fight. Neighbors described seeing both of them on the ground, with Martin at one point having the upper hand. But Zimmerman chose to pursue Martin through the neighborhood. Before that, he was safely in his car, which he could have locked and stayed in or simply driven away. While he was in the car, he was in contact with the 911 operators, who told him officers were on the way—a condition vastly safer than sitting around not talking to the people who send out the cops.

But he expressly ignored that operator, got out of his car and went tromping through the neighborhood, playing Racist Elmer Fudd, hunting down "an A and B student who majored in cheerfulness." As with many Stand Your Ground shootings, Zimmerman might never see jail time.

And even that, too, is unsurprising and familiar.

In 2007, a 61-year-old Texas man named Joe Horn shot and killed two illegal aliens. He saw them breaking into a neighbor's house and called the police. The 911 operator repeatedly told him not to go outside. (As with Zimmerman, the audio of the call is horrifying.) Horn ignored them, went outside, and shot both men in the back, which was confirmed by a plainclothes detective on the scene. The man left his house, placing himself in danger, then claimed self-defense for executing two human beings.

I missed the Horn shooting when it originally happened, and only found out about it when I—for reasons that today seem incredibly misguided—live blogged Glenn Beck's FOX News Show on April 15, 2009, the first nationwide Tea Party. Here's what I wrote:

Beck has [Horn] on as a hero in a flourish of theater so mind-rendingly horrifying that it really deserves being written exactly like theater (you can watch it here; click to 3:00 in):

BECK:(to Horn) You saw people breaking into your neighbor's house... You shot them.

(FOX NEWS GRAPHIC ON BOTTOM OF SCREEN: SHOT 2 ILLEGALS.)

HORN: When your life is on the line, and you take a human life, I wanted to live. I wanted to live. And I was not gonna let those two men kill me. And I can assure you, if they'da got to me, they woulda killed me. So I shot 'em.

(Crowd cheers.)

Photo by Red Huber / Orlando Sentinel.

"Mobutu Sese Seko" is founder of the blog Et tu, Mr. Destructo? and a former political blogger for Vice.com. He has also contributed to GQ.com and SomethingAwful.com. You can follow him on Twitter and Facebook and email him here.